Double antenna

The doublet antenna is essentially a balanced system and each half of the top plus each wire in the feed line must be equal in length. The antenna top is not cut to resonate at any particular frequency (unlike the half-wave dipole), and any length may be chosen to suit an individual location. The key to the doublet antenna is the form of feeder used. Open wire or balanced feeders are able to operate as part of the actual antenna itself, not just feeding the power from an unbalanced source. The balanced feeder or open wire feeder is able to operate with standing waves along its length.

Standing waves are a feature of radiating wires, but in the case of the open wire feeder, it consists of two equal length close spaced wires.

As these carry equal and opposite currents their radiation cancels. However the feeder still remains part of the overall antenna itself. See full list on electronics-notes. The feeder can be either open wire or what is termed ladder line. This can be either 300Ω or 450Ω.

Also the length of the feeder can be cut meet the requirements of the installation. When feeding an antenna of this type it is found that it can present an impedance over a wide range. Accordingly it is necessary to use an antenna tuning unit to ensure that the transmitter itself is presented with the required impedance.

The antenna tuning unit used should be able to match impedances over a wide range, and it must also have a balanced output connection. If it does not, then an external balun is required so that the unbalanced to balanced transition is present. Baluns can be bought or made. Essentially they are simple in their construction provided that the right components and tools are available.

Particularly key is the former on which the balun is wound. Typically this is a torroid and it must have the required RF properties and RF power handl. Although it is always best to use an antenna tuning unit with a doublet antenna, it is possible to arrange the antenna so that this may not always be needed. Although any length of balanced feeder can be used with the doublet, the impedance match is best if the total length of one leg of the antenna and feeder, i. Using this approach the impedance, around 50Ω is low and mainly resistive. As might be expected there are many variants of doublet antennas that have different properties.

Over the years many different antenna designs have been created that are based on the doublet antenna concept. G5RV antenna : The G5RV is a doublet antenna with specific lengths that makes it suitable for operation on a variety of amateur radio bands whilst maintaining a good match. It can still be used today on a variety of amateur bands, although operating it on some of the newer bands, and also with solid state transmitter PAs it requires the use of an antenna tuning matching unit.

When considering the use of a doublet antenna it is worth considering both the advantages and also the disadvantages. As such doublet antennas can provide an ideal solution to many HF antenna requirements. A doublet antenna (dipole), cut for meters, will not work on meters because MHz is an even harmonic multiple of 3. The result would be a very high (impractical) impedance at MHz - whereas the impedance of an 80.

In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna. The dipole is any one of a class of antennas producing a radiation pattern approximating that of an elementary electric dipole with a radiating structure supporting a line current so energized that the current has only one node at each end. It is made of coax cable, instead of a single strand of copper wire. The braided copper shield of the coax is the actual RF radiator, and the center conductor acts like a balun or matching transformer to provide a DC ground. A popular misconception about vertical antennas for the low bands is that they must have elaborate ground systems.

Here’s a vertical antenna for and 16 fed with a single feed line that is simple, effective, and requires no ground system. What is a doublet antenna? Will a doublet antenna work on meters?

By adding a second OTA antenna you can increase your signal strength. If you already have an amplifier to boost your signal a second antenna can help to increase the consistency of your coverage. Depending on how the signal is being sent, obstructions can interfere with the delivery of the signal path.

Adding a second antenna can increase the signal path coverage and give you a more consistent signal. To accomplish this you will need a combiner or couplerthat can combine the two antennas together. I would recommend that you use two identical antennas. Try experimenting with placement and proper directional pointing. If you are not sure where your broadcast towers are you can use our Station Locator Tool to locate broadcast towers in your area.

The basic idea is to have each antenna pointing at different broadcast towers. You could use a rotary antenna to solve this problem, but if you are splitting the signal to multiple TV’s this could be an issue. With the two-antenna setup, this can resolve that problem.

Again the same rules apply. An antenna coupler or joiner will be needed. Below is a diagram by Channel Master explaining the setup using their joiner.

It may take some tweaking to get the antennas pointed in the proper directions. Just be patient and rescan your tuner to see what channels you gained. Antenna stacking is the process of taking two HD antennas and placing one on top or near each other.

It is important to get the spacing and phasing correct for both antennas. It is best to use two different styles of antennas that will complement each other. You can try experimenting and built one on your own.

The example below shows a rabbit ear style combined with a bow-tie antennato better capture the UHF and VHF bands. By combining these two styles of OTA antennas you can increase your overall coverage. Fairpoint Farms shows his HD stacked antennas in the video below. It allowed him to gain many stations from a long way out.

Combining two HD antennas can have a positive impact on your overall channel coverage and reception. If you are looking to increase your signal coverage it may be worth experimenting. Please feel free to comment below for questions or if you have experimented with any of these types of setups. Stacking TV antennas to improve performance.

I installed stacked TV antennas in weak signal areas for over decades. In the beginning I had to experiment to find the best combination of antennas and find the proper spacing distance between the antennas. Ubiquiti Networks Authorized Distributor - complete online store.

Free 2-day Shipping On Millions of Items. Wholesaler to Small Retailers. Wi-Fi antenna : A dual Wi-Fi antenna is a pair of identical antennas on a wireless router or Wi-Fi -equipped device, intended to eliminate signal fading and dead spots. Dual Wi-Fi antennas operate on a principle known as antenna diversity, which offers two different reference points for signal reception or transmission (or both) and uses. Build a double bazooka antenna.

Scroll down to see all the diagrams. Dave Tadlock: KG0ZZ Dave has lots of ham radio videos (and others) on. I’ve personally used some of his shared information for my own use and have been quite successful following his videos. Give him a visit when you can.

It may be necessary to add a Cantenna to your setup instead of another DB8. The ClearStreamis our newest ClearStream antenna. It is a smaller, high gain VHF antenna that will do better at picking up the lower VHF signals than the DBwhich covers the entire UHF band. Putting DBantennas together is NOT recommended or supported by. Taylor Vee Antenna for 20m.

Double Bobtail Antenna for 20m. Stack two of them together cut at around channel with an insulated center hub and balun, and in essence you will have a C-double loop antenna , just like the Clear Stream. Collinear Vertical Antenna 6dB-Gain for 2m, 1. Look at the gain numbers for my antenna that is in the hands of a patent attorney right now.